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Discrepancy between the composition of some commercial cat foods and their package labelling and suitability for meeting nutritional requirements
Abstract
Objective:
To investigate if the label information and nutrient composition of commercial cat foods are accurate and compliant with the Australian Standard (AS 5812-2011) and if they meet the nutritional requirements of an adult cat.
Methods:
A chemical analysis of 10 wet and 10 dry commercial cat foods labelled as 'nutritionally complete' for the adult cat was performed. The results were compared with the package composition values, the Australian Standard and the unique dietary requirements of the cat. In addition, the results of the chemical analysis were compared with the nutrient requirements published by the Association of the American Feed Control Officials and the National Research Council.
Results:
When compared with the Australian Standard, 9 of the 20 cat foods did not adhere to their 'guaranteed analysis' and 8 did not adhere to the standards for nutrient composition. Also, various deficiencies and excesses of crude protein, crude fat, fatty acid and amino acid were observed in the majority of the cat foods.
Conclusions:
The results of this study highlight a need for an improved method of ensuring that label information and nutrient composition are accurate and comply with the Australian Standard (AS 5812-2011) to ensure the adult cat's unique dietary requirements are being met by commercial adult cat food.
... Przeprowadzone badania [10][11][12][13][14][15][16] wykazały, iż wciąż nie wszystkie etykiety dostępnych na rynku gotowych karm dla psów i kotów zawierają kompletne i rzetelne informacje na temat składu chemicznego paszy oraz jej stosowania. W badaniach przeprowadzonych w Brazylii, USA i Australii [12,13,17] ustalono, że zawartość mikroelementów, kwasów tłuszczowych, a także profil aminokwasowy wielu karm dla psów i kotów nie są zgodne z deklarowanymi na etykiecie. ...
... Przeprowadzone badania [10][11][12][13][14][15][16] wykazały, iż wciąż nie wszystkie etykiety dostępnych na rynku gotowych karm dla psów i kotów zawierają kompletne i rzetelne informacje na temat składu chemicznego paszy oraz jej stosowania. W badaniach przeprowadzonych w Brazylii, USA i Australii [12,13,17] ustalono, że zawartość mikroelementów, kwasów tłuszczowych, a także profil aminokwasowy wielu karm dla psów i kotów nie są zgodne z deklarowanymi na etykiecie. Amerykańskie i kanadyjskie badania [12,16,18] wykazały, iż część z analizowanych karm komercyjnych nie spełnia przyjętych w tych krajach norm dotyczących zawartości makroi mikroelementów. ...
Consumer awareness among dog owners is constantly growing – when purchasing ready-made food, they pay more and more attention to the chemical composition of the product; hence its adequate description becomes important in marketing activities. The aim of the study was to compare the macronutrient content of ready-made complete feeds for adult dogs declared on the label with the actual state and with the FEDIAF guidelines. The conducted Wenden analysis showed that the tested dry feeds (n = 14) in dry matter contained on average more total protein (p < 0.01) and less crude fiber (p < 0.01) than declared on the label – 23.68 respectively % vs. 20.58% and 3.25% vs. 2.11%. Moist food (n = 16) had on average less crude fat (p < 0.05) than declared by the producers – 18.92% vs 23.05% DM. All the feeds tested met the FEDIAF requirements for protein content. One dry food did not meet the fat content standards. Significant differences between the actual content of protein and fiber in dry foods and fat in wet foods, as compared to the manufacturers' declarations, indicate the need for constant verification of the accuracy of the information provided on the labels of dog foods. Inconsistent with the actual state of data on the chemical composition of the feed may lead to macronutrient deficiencies and an inadequate energy balance in the diet of dogs.
... In this and other studies, it is common to see that the amounts of some essential elements, selenium and manganese among them, are usually over-supplemented, sometimes exceeding the established legal limits [36,37]. In that sense, our results agree with others already published, highlighting the existing discrepancies between what the pet industry says that a food provides and what it really has in terms of essential elements The fact that only a minority of brands comply with all nutrient content claims listed on their labels [38,39] indicates that the need for legislation in this regard is urgent. Apart from not complying with the legislation related to labels and being, at times, misleading advertising, in certain circumstances the health of the pets themselves can even be put at risk. ...
... In that sense, our results agree with others already published, highlighting the existing discrepancies between what the pet industry says that a food provides and what it really has in terms of essential elements. The fact that only a minority of brands comply with all nutrient content claims listed on their labels [38,39] indicates that the need for legislation in this regard is urgent. Apart from not complying with the legislation related to labels and being, at times, misleading advertising, in certain circumstances the health of the pets themselves can even be put at risk. ...
Dry feed for pets lacks specific legislation regarding maximum residue limits for inorganic elements. The aim of the present study was to determine the content of 43 inorganic elements in dog and cat feed, studying whether there were differences according to the supposed quality of the food and performing the risk assessment for health. Thirty-one and thirty packages of pelleted dry food for cats and dogs, respectively, were analyzed. After acidic microwave-assisted digestion, elements were detected and quantified by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In general, we did not observe important differences in the content of elements according to the supposed quality of the brand. Among trace elements, selenium and manganese are above the dietary reference value. Arsenic and mercury showed the highest acute hazard indexes, which make them risk factors for the health of dogs and cats. Aluminum, uranium, antimony and vanadium contents were above the toxic reference value and showed the highest acute hazard indexes. It is necessary to improve the legislation regarding the food safety of pets, for their health and to protect the rights of consumers.
... Cats are obligate carnivores with strict nutritional requirements (Macdonald & Rogers, 1984). Some commercial pet foods have been found not to provide some essential elements (Gosper, Raubenheimer, Machovsky-Capuska, & Chaves, 2016;Zafalon et al., 2020) and macronutrients (Hewson-Hughes et al., 2011). Furthermore, the proteins in pet foods can be derived from both animal and plant sources, but plant proteins have lower digestibility (Kanakubo, Fascetti, & Larsen, 2015;Neirinck, Istasse, Gabriel, Van Eenaeme, & Bienfait, 1991), lower bioavailability (Zafalon et al., 2020) and a less complete amino acid profile (Donadelli, Aldrich, Jones, & Beyer, 2019) than animal proteins. ...
Domestic cats (Felis catus) that roam outdoors have increased exposure to hazards to their health and welfare. Outdoor cats can themselves present a hazard to biodiversity conservation and wild animal welfare. Approaches to reducing predation of wildlife by cats might also bring benefits to cats by reducing their roaming and associated risks. We investigated ranging behaviors of domestic cats that regularly captured wild prey, and that had restricted or unrestricted outdoor access. We tested whether interventions aimed at reducing predation also affected their spatial behavior. We evaluated cat bells, Birdsbesafe collar covers, using a “puzzle feeder”, provision of meat‐rich food, object play, and a control group. Seventy‐two cats in 48 households in England completed the 12‐week trial in spring 2019. Home ranges were small (median AKDE95 = 1.51 ha). Cats with unrestricted outdoor access had 75% larger home ranges, 31% greater daily distances traveled, and reached 46% greater maximum distances from home, than cats with restricted outdoor access. None of the treatments intended to reduce predation affected cat ranges or distances traveled. While owners might use interventions to reduce predation, the only effective means of reducing cat roaming and associated exposure to outdoor hazards was restriction of outdoor access. While some interventions, like object play and dietary changes, can reduce domestic cat predation of wildlife, we found that these measures do not affect cat roaming behavior. Restricting access to the outdoors, even partially, does reduce the extent of cat ranging and likely reduces associated exposure to outdoor hazards.
... While human grade, natural, organic or holistic products are not recognized by many practitioners to be superior to their conventional counterparts, it is positive to note the increased awareness or concern of owners feeding PB regarding the labelling of a diet being complete and balanced. While a statement of nutritional adequacy in accordance with industry guidelines is not a guarantee that the product is indeed appropriate for the animal for which it is intended to be fed [60,61], it is a benchmark by which pet foods are compared and is a minimum standard to ensure nutritional sufficiency. ...
Background
Cats, being obligate carnivores, have unique dietary requirements for nutrients most commonly found in dietary ingredients of animal origin. As such, feeding a diet devoid of animal-derived ingredients has been postulated as a possible cause of nutrient imbalances and adverse health outcomes. A small proportion of cat owners feed strictly plant-based diets to the cats in their care, yet the health and wellness of cats fed these diets has not been well documented.
Results
A total of 1325 questionnaires were complete enough for inclusion. The only exclusion criterion was failure to answer all questions. Most cats, 65% (667/1026), represented in the survey were fed a meat-based diet and 18.2% (187/1026) were fed a plant-based diet, with the rest fed either a combination of plant-based with meat-based (69/1026, 6.7%) or indeterminable (103/1026, 10%). Cat age ranged from 4 months to 23 years, with a median of 7 years, and was not associated with diet type. No differences in reported lifespan were detected between diet types. Fewer cats fed plant-based diets reported to have gastrointestinal and hepatic disorders. Cats fed plant-based diets were reported to have more ideal body condition scores than cats fed a meat-based diet. More owners of cats fed plant-based diets reported their cat to be in very good health.
Conclusions
Cat owner perception of the health and wellness of cats does not appear to be adversely affected by being fed a plant-based diet. Contrary to expectations, owners perceived no body system or disorder to be at particular risk when feeding a plant-based diet to cats. This study collected information from cat owners and is subject to bias, as well as methodological limitations. Further research is warranted to determine if these results are replicable in a prospective investigation.
... 41.0% and 22.3%, respectively. The total PUFA content ranged from 5.1% to 47.1% for the wet foods [24]. In samples collected and studied in this study, the average amounts of these acids in fat extracted from appropriate samples are as follows Presented results and statistical analysis show that fat chemical composition and shelf life do not directly relate to the price of a given group. ...
This study aims to compare the quality of fat extracted from different priced dry pet food for adult cats through classical and instrumental methods: pressure differential scanning calorimetry (PDSC), Fourier transform infrared spectroscopy (FT-IR) or gas chromatography (GC). Fat extracted from pet food was examined for induction time (IT), fatty acid composition, free fatty acid (FFA) content and peroxide value with the use of PDSC, GC, acid–base and iodometric titration, respectively. FT-IR data from the selected spectral regions correlate with the value of oxidation IT or the content of FFA. This resulted in construction of a reference model for IT with the following statistical features: R
calibration = 0.917 (RMSEC = 28.0) and R
validation = 0.841 (RMSEP = 34.6). For fatty acid content, model statistics were as follows: R
calibration = 0.912 (RMSEC = 0.61) and R
validation = 0.856 (RMSEP = 0.75). Discriminant model that uses spectral data alone, calculated with performance index 83.7 allowed distinguishing the studied pet food samples due to the price. Studies conducted proved PDSC and IR as reliable analytical techniques to control and monitor the quality of dry pet food for cats. Considering quality of the studied samples, it was proved that low-priced pet foods can be stored longer than premium-priced ones, while former is nutritionally more beneficial for adult cats.
... Furthermore, labelling compliance was determined to be poor [35]. Unfortunately, these phenomena appear to be common within the pet food industry, with multiple accounts of commercial pet foods failing to meet labelling standards, guaranteed analysis, industry recommended nutrient profiles, or containing ingredients other than those listed on the packaging [89][90][91]. Thus, this does not appear to be an issue exclusive to plant-based diets. ...
People who avoid eating animals tend to share their homes with animal companions, and moral dilemma may arise when they are faced with feeding animal products to their omnivorous dogs and carnivorous cats. One option to alleviate this conflict is to feed pets a diet devoid of animal ingredients—a ‘plant-based’ or ‘vegan’ diet. The number of pet owners who avoid animal products, either in their own or in their pets’ diet, is not currently known. The objective of this study was to estimate the number of meat-avoiding pet owners, identify concerns regarding conventional animal- and plant-based pet food, and estimate the number of pets fed a plant-based diet. A questionnaire was disseminated online to English-speaking pet owners (n = 3,673) to collect data regarding pet owner demographics, diet, pet type, pet diet, and concerns regarding pet foods. Results found that pet owners were more likely to be vegetarian (6.2%; 229/3,673) or vegan (5.8%; 212/3,673) than previously reported for members of the general population. With the exception of one dog owned by a vegetarian, vegans were the only pet owners who fed plant-based diets to their pets (1.6%; 59/3,673). Of the pet owners who did not currently feed plant-based diets but expressed interest in doing so, a large proportion (45%; 269/599) desired more information demonstrating the nutritional adequacy of plant-based diets. Amongst all pet owners, the concern most commonly reported regarding meat-based pet foods was for the welfare of farm animals (39%; 1,275/3,231). The most common concern regarding strictly plant-based pet foods was regarding the nutritional completeness of the diet (74%; 2,439/3,318). Amongst vegans, factors which predicted the feeding of plant-based diets to their pets were concern regarding the cost of plant-based diets, a lack of concern regarding plant-based diets being unnatural, and reporting no concern at all regarding plant-based diets for pets. Given these findings, further research is warranted to investigate plant-based nutrition for domestic dogs and cats.
... In particular, nutritional ecology studies have demonstrated that the amounts, concentrations, and ratios of macronutrients (protein, carbohydrate, and lipid) in foods and diets can strongly influence animal foraging behavior, including homeostatically regulated intake in the face of both optimal and imbalanced nutritional environments (Raubenheimer and. This macronutrient-focused approach has been broadly applied from individuals to populations , and across a wide range of nutritionally influenced research disciplines, including wildlife ecology and conservation (Raubenheimer and Simpson 2006, Rothman et al. 2011, Coogan et al. 2014, human-wildlife conflict (Coogan and Raubenheimer 2016), biological invasions (Sword et al. 2010, Machovsky-Capuska et al. 2016b, Peneaux et al. 2017, and companion animal nutrition (Raubenheimer et al. 2015a, Gosper et al. 2016. ...
There is growing interest in the question of how urbanization affects the ecology of birds, across timescales from relatively short‐term physiological responses to long‐term evolutionary adaptation. The ability to gain the required nutrients in urban habitats is a key trait of successful urban birds. Foraging behavior, in itself, increasingly is recognized as a complex nutritional phenomenon, where the ratios, proportions, and amounts of macronutrients (protein, carbohydrate, and lipid) in foods, meals, and diets have been shown to exert a driving influence. Yet, despite the rising trend of urbanization, the importance of food quality and quantity in urban ecology, and the growing evidence demonstrating the pervasive and sometimes complex role of macronutrients in foraging behavior, the nutritional ecology of urban birds remains poorly understood. Here, we review the foraging behavior and role of macronutrients in the ecology of urban birds and demonstrate how incorporating a multidimensional approach to nutrition can provide new insights into their urban ecology. To that end, we demonstrate how a macronutrient‐based view can aid in understanding the relationships between natural, anthropogenic, and supplementary foods. We then provide an overview of multidimensional nutritional niche concepts that can be used to generate explanatory and predictive models for urban bird ecology. We conclude that multidimensional nutritional ecology provides an appropriate framework for understanding the roles that nutrition plays in the relationships between urban birds and their environments.
Predation by domestic cats Felis catus can be a threat to biodiversity conservation,1, 2, 3 but its mitigation is controversial.⁴ Confinement and collar-mounted devices can impede cat hunting success and reduce numbers of animals killed,⁵ but some owners do not wish to inhibit what they see as natural behavior, perceive safety risks associated with collars, or are concerned about device loss and ineffectiveness.⁶,⁷ In a controlled and replicated trial, we tested novel, non-invasive interventions that aim to make positive contributions to cat husbandry, alongside existing devices that impede hunting. Households where a high meat protein, grain-free food was provided, and households where 5–10 min of daily object play was introduced, recorded decreases of 36% and 25%, respectively, in numbers of animals captured and brought home by cats, relative to controls and the pre-treatment period. Introduction of puzzle feeders increased numbers by 33%. Fitting Birdsbesafe collar covers reduced the numbers of birds captured and brought home by 42% but had no discernible effect on mammals. Cat bells had no discernible effect. Reductions in predation can be made by non-invasive, positive contributions to cat nutrition and behavior that reduce their tendency to hunt, rather than impede their hunting. These measures are likely to find support among cat owners who are concerned about the welfare implications of other interventions.
Practical relevance
Although most skin lesions occur due to diseases primarily affecting the skin, some reflect important systemic diseases. Such lesions may relate directly to the systemic disease, or may occur due to secondary skin diseases that develop because of immunosuppression. Early recognition of skin changes as a marker of systemic disease will maximise patient outcomes.
Clinical challenges
In older or clearly debilitated cats presenting with skin disease, the potential for underlying systemic disease is often readily apparent. Similarly, cats presenting with severe ulcerative or multifocal nodular skin lesions, or with concurrent signs of systemic illness, will more instinctively prompt systemic evaluation. More challenging is the cat presenting with alopecic, scaling, erythemic and/or mildly crusted skin disease, with or without pruritus; hypersensitivities and infectious dermatoses are the most common considerations, but occasionally systemic disease underlies the skin changes. Knowing when screening laboratory testing, body imaging or other systemic diagnostics are indicated is not always straightforward.
Evidence base
This article reviews cutaneous presentations of systemic diseases reported in the veterinary literature, and discusses important differential diagnoses. The author draws on clinical experience, published data on disease prevalence and case evaluations, and expert opinions on approach to common systemic problems to provide guidance on when investigation for underlying systemic disease is most appropriate.
A recent area of progress in nutritional ecology is a growing awareness that nutritional phenotypes are best understood in a multidimensional context, where foraging is viewed as a process of balancing the intake and use of multiple nutrients to satisfy complex and dynamic nutrient needs. Numerous laboratory studies have shown that this view can yield novel insights into unresolved questions and provide a framework for generating new hypotheses. By contrast, progress with this multidimensional view has been slow in the arena of ultimate interest to functional biologists, the field. One reason for this is that the Geometric Framework for nutrition that has been extensively used in laboratory experiments focuses on amounts of nutrients (e.g., required, eaten, or retained), and such data are typically very difficult or impossible to collect for most free-ranging animals. Further, many problems in field-based nutritional ecology involve comparisons of mixtures that are expressed as proportions (e.g., food, diet, body, or fecal compositions), rather than absolute amounts. As yet, however, no geometric framework has been established in nutritional ecology for this. Here I recommend an approach for the geometric analysis of nutritional mixtures, and illustrate its use in a variety of contexts by reanalyzing published data. Despite its simplicity, this approach holds considerable promise for furthering the study of field-based nutritional ecology.
The domestic hypercarnivores cat and mink have a higher protein requirement than other domestic mammals. This has been attributed to adaptation to a hypercarnivorous diet and subsequent loss of the ability to downregulate amino acid catabolism. A quantitative analysis of brain glucose requirements reveals that in cats on their natural diet, a significant proportion of protein must be diverted into gluconeogenesis to supply the brain. According to the model presented here, the high protein requirement of the domestic cat is the result of routing of amino acids into gluconeogenesis to supply the needs of the brain and other glucose-requiring tissues, resulting in oxidation of amino acid in excess of the rate predicted for a non-hypercarnivorous mammal of the same size. Thus, cats and other small hypercarnivores do not have a high protein requirement per se, but a high endogenous glucose demand that is met by obligatory amino acid-based gluconeogenesis. It is predicted that for hypercarnivorous mammals with the same degree of encephalisation, endogenous nitrogen losses increase with decreasing metabolic mass as a result of the allometric relationships of brain mass and brain metabolic rate with body mass, possibly imposing a lower limit for body mass in hypercarnivorous mammals.
Cats have obligatory requirements for dietary nutrients that are not essential for other mammals. The present review relates these idiosyncratic nutritional requirements to activities of enzymes involved in the metabolic pathways of these nutrients. The high protein requirement of cats is a consequence of the lack of regulation of the aminotransferases of dispensable N metabolism and of the urea cycle enzymes. The dietary requirements for taurine and arginine are consequences of low activities of two enzymes in the pathways of synthesis that have a negative multiplicative effect on the rate of synthesis. Cats have obligatory dietary requirements for vitamin D and niacin which are the result of high activities of enzymes that catabolise precursors of these vitamins to other compounds. The dietary requirement for pre-formed vitamin A appears to result from deletion of enzymes required for cleavage and oxidation of carotenoids. The n-3 polyunsaturated fatty acids (PUFA) requirements have not been defined but low activities of desaturase enzymes indicate that cats may have a dietary need for pre-formed PUFA in addition to those needed by other animals to maintain normal plasma concentrations. The nutrient requirements of domestic cats support the thesis that their idiosyncratic requirements arose from evolutionary pressures arising from a rigorous diet of animal tissue. These pressures may have favoured energy conservation through deletion of redundant enzymes and modification of enzyme activities to result in metabolites more suited to the cat's metabolism. However, this retrospective viewpoint allows only recognition of association rather than cause and effect.
The effect of excesses of the branched-chain amino acids (BCAA), particularly leucine, on growth, food intake and plasma amino acid concentrations were investigated in kittens. Effects of excess leucine were tested in kittens fed five basal diets that varied in their nitrogen and amino acid contents. Compared to rats, kittens were much less sensitive to excesses of the BCAA. Addition of 10% leucine to basal diets that provided nitrogen just at or below the minimal requirement of kittens resulted in no change or increased growth and food intake of kittens when the isoleucine and valine concentrations in the basal diet were just at or slightly in excess of the kitten's minimal requirements for those amino acids. An adverse effect of leucine added to low nitrogen basal diets was observed only when isoleucine and valine were provided below the kitten's requirement (80% of requirement). When basal diets containing adequate nitrogen (24% amino acids) were tested, the addition of leucine (10%) resulted in an adverse effect when isoleucine and valine were provided at 80% of the kitten's requirement and in mild growth depressions when isoleucine and valine were provided at 1.1 times the requirement. Leucine-induced growth depression was alleviated by the addition of isoleucine and valine at 0.5%, indicating that excess leucine caused a BCAA antagonism or an amino acid imbalance. With the addition of leucine to the basal diets, there were consistent decreases in concentrations of alanine and tyrosine in plasma but no consistent depressions in the concentrations of isoleucine and valine.
Four groups of five kittens each were individually fed for 6 wk either a purified control diet containing 0.5% methionine (Met) (based on 18% casein supplemented with arginine, cystine and threonine) or one of three experimental diets containing an additional 2, 3 or 4% L-Met. The diets with added Met caused a reduction in food intake (FI) on the second day and a negative body weight gain (BWG), in proportion to the level of added Met. After 10 d, kittens fed the 2 and 3% Met diets increased their FI and had positive BWG. During the last 10 d of the experiment, the control, 2% Met and 3% Met groups had BWG of 28, 15 and 0 g/d, respectively. Kittens given the 4% Met diet showed no adaptation and continued to lose weight. In these kittens plasma concentration of Met was 50-70 times and cystathionine about three times greater than in control kittens. Four male kittens were fed the same 4% Met diet for 6 wk and then switched to a diet containing 4% L-Met plus 4% glycine (Gly) for 12 d. Average daily FI was 21.4 +/- 1.3 g with 4% Met and 48.5 +/- 2.5 g after the addition of Gly, and BWG went from negative to positive. These results indicate that growing kittens are more sensitive than rats to excess Met and have a limited adaptive capacity. Kittens did not grow normally when the diet contained 2% or more dietary Met, which was equivalent to 0.6 g Met/(kg body wt.d).
To determine the essential fatty acid (EFA) requirements of the cat, specific pathogen-free kittens were fed either a linoleate-deficient diet or one of two diets containing 5% safflower seed oil (SSO) with or without 0.2% tuna oil. The diets were fed for 82-101 weeks beginning at 3 months of age. The results showed that linoleate is an essential fatty acid for the cat. Linoleate deficiency resulted in reduced feed efficiency (in males), high rates of transepidermal water loss, poor skin and coat condition, and fatty liver. These manifestations of EFA deficiency were prevented by SSO. Tuna oil had no additional effect. Analyses of the fatty acid composition of plasma, erythrocytes and liver lipids revealed that linoleate deficiency caused changes that were qualitatively, but not quantitatively similar to EFA deficiency in the rat. When SSO was provided, linoleate was elongated and desaturated at the delta 5 position to form 20:2n6 and 20:3(5,11,14). However, there was negligible conversion of linoleate to arachidonate. These results indicate that linoleate has specific functions as an EFA, independent of arachidonate synthesis and prostaglandin formation.
1. There is controversy regarding the capacity of the cat to convert 18:2ω6 to 20:4ω6 and the ability of the essential fatty acid (EFA)-deficient cat to produce 20:3ω9.
2. This paper reports the isolation and identification of 20: 3ω9 from kidney phospholipids of EFA-deficient cats.
3. The results suggest that the cat is capable of limited synthesis of 20:4ω6 using a Δ5- and Δ8-desaturase.
Cats have a requirement for dietary protein two to three times that of omnivores and herbivores. This was reported to be due to the hepatic catabolic enzymes of this species being set to a permanently high level and, therefore, showing little adaptation to low dietary protein. A major mechanism for adapting to dietary protein in other species is amino acid oxidation (hereafter referred to as protein oxidation), and the objective of this study was to determine whether protein oxidation in cats was correlated with protein intake. Net protein and net fat oxidation in six adult cats were studied directly from gas exchanges using indirect calorimetry, after feeding moderate protein (MP; 35% energy) and high protein (HP; 52% energy) diets. Protein oxidation was significantly higher (P < 0.05) when cats were fed the HP diet (28.4 plus minus 0.7 mg/min) rather than the MP diet (20.4 plus minus 0.8 mg/min). Fat oxidation was significantly higher (P < 0.05) when cats consumed the MP diet (9.0 plus minus 0.7 mg/min) rather than the HP diet (4.7 plus minus 0.5 mg/min). Protein oxidation was significantly correlated (linear regression, R(2) = 46.0, P < 0.05) with protein intake such that the mean ratio of 18-h oxidation: 18-h intake was 1.2 on both diets. Fat oxidation was significantly correlated (linear regression, R(2) = 18.9, P < 0.05) with fat intake such that the mean ratio of 18-h fat oxidation: 18-h fat intake was 1.1 (MP) and 0.9 (HP). This study demonstrated that cats adapt net protein oxidation at these levels of protein intake, and the reason for the high dietary protein requirement of this species is, therefore, unclear.
A simplified protocol to obtain fatty acid methyl esters (FAME) directly from fresh tissue, oils, or feedstuffs, without prior organic solvent extraction, is presented. With this protocol, FAME synthesis is conducted in the presence of up to 33% water. Wet tissues, or other samples, are permeabilized and hydrolyzed for 1.5 h at 55 degrees C in 1 N KOH in MeOH containing C13:0 as the internal standard. The KOH is neutralized, and the FFA are methylated by H(2)SO(4) catalysis for 1.5 h at 55 degrees C. Hexane is then added to the reaction tube, which is vortex-mixed and centrifuged. The hexane is pipetted into a gas chromatography vial for subsequent gas chromatography. All reactions are conducted in a single screw-cap Pyrex tube for convenience. The method meets many criteria for fatty acid analysis, including not isomerizing CLA or introducing fatty acid artifacts. It is applicable to fresh, frozen, or lyophilized tissue samples, in addition to oils, waxes, and feedstuffs. The method saves time and effort and is economical when compared with other methods. Its unique performance, including easy sample preparation, is achieved because water is included rather than eliminated in the FAME reaction mixtures.
How well can you answer pet owners' questions about proper diet and feeding? Canine and Feline Nutrition, 3rd Edition describes the role of nutrition and its effects upon health and wellness and the dietary management of various disorders of dogs and cats. By using the book's cutting-edge research and clinical nutrition information, you'll be able to make recommendations of appropriate pet food and proper feeding guidelines. Pet nutrition experts Linda P. Case, MS, Leighann Daristotle, DVM, PhD, Michael G. Hayek, PhD, and Melody Foess Raasch, DVM, provide complete, head-to-tail coverage and a broad scope of knowledge, so you can help dog and cat owners make sound nutrition and feeding choices to promote their pets' health to prolong their lives. Tables and boxes provide quick reference to the most important clinical information. Key points summarize essential information at a glance. A useful Nutritional Myths and Feeding Practices chapter dispels and corrects common food myths.New clinical information covers a wide range of emerging nutrition topics including the role of the omega-3 and omega-6 fatty acid families in pet health and disease management. Coverage of pet food safety and pet food ingredients includes both commercially and home-prepared foods and provides answers to pet owners' questions on these topics. Completely updated content reflects the latest findings in clinical nutrition research. Information regarding functional ingredients and dietary supplementation provides a scientifically based rationale for recommending or advising against dietary supplements. Guidelines for understanding pet food formulations and health claims differentiate between "market-speak" and actual clinical benefits for patients, with practice advice for evaluating and selecting appropriate foods.
Nutrition has long been considered more the domain of medicine and agriculture than of the biological sciences, yet it touches and shapes all aspects of the natural world. The need for nutrients determines whether wild animals thrive, how populations evolve and decline, and how ecological communities are structured.The Nature of Nutritionis the first book to address nutrition's enormously complex role in biology, both at the level of individual organisms and in their broader ecological interactions. Stephen Simpson and David Raubenheimer provide a comprehensive theoretical approach to the analysis of nutrition--the Geometric Framework. They show how it can help us to understand the links between nutrition and the biology of individual animals, including the physiological mechanisms that determine the nutritional interactions of the animal with its environment, and the consequences of these interactions in terms of health, immune responses, and lifespan. Simpson and Raubenheimer explain how these effects translate into the collective behavior of groups and societies, and in turn influence food webs and the structure of ecosystems. Then they demonstrate how the Geometric Framework can be used to tackle issues in applied nutrition, such as the problem of optimizing diets for livestock and endangered species, and how it can also help to address the epidemic of human obesity and metabolic disease.
The pathologic changes of essential fatty acid (EFA) deficiency were studied in specific-pathogen-free, domestic shorthair cats which were fed purified diets for 1.5 to 2.5 years. Cats fed an EFA-deficient diet exhibited signs of deficiency: severe fatty degeneration of the liver, excessive fat in the kidneys, dystrophic mineralization of the adrenal glands, degeneration of the testes, and hyperkeratosis of the skin. Minor clinical pathologic changes were consistent with liver damage. Fatty acid analyses of plasma lipids revealed low concentrations of linoleate and other n6-fatty acids, and high concentrations of n7- and n9-fatty acids, consistent with EFA deficiency. These signs of deficiency were prevented by including safflower seed oil in the diet at a concentration to supply linoleate at 6.7% of dietary energy. Therefore, linoleate is an EFA for the cat, despite negligible conversion of linoleate to arachidonate in cat liver. However, in cats fed a diet containing linoleate, but lacking arachidonate, there was mild mineralization of the kidneys, and the neutral fat content of the liver was slightly higher than that of cats fed a diet containing arachidonate and other long-chain polyunsaturated fatty acids. Also, 2 of the 19 cats fed arachidonate-deficient diets developed unusual inflammatory skin lesions. In cats fed a diet containing hydrogenated coconut oil, safflower seed oil, and chicken fat, fatty livers developed despite the presence of high levels of linoleate. The fatty livers appeared to result from a specific deleterious effect of the medium-chain triglycerides in hydrogenated coconut oil. Most of the organ pathologic changes of EFA deficiency in the cat can be prevented by feeding dietary linoleate. Linoleate meets the EFA requirement for functions which depend on proper membrane structure: growth, lipid transport, normal skin and coat condition, and maintenance of the epidermal permeability barrier. However, dietary arachidonate is required by the cat for functions which depend on eicosanoid formation, such as reproduction and blood platelet aggregation.
Kohlenhydratstoffwechsel der Katze 2. Verdauung von Stärke
In 6 Verdauungsversuchen und 5 post-mortem-Experimenten erhielten 56 erwachsene Katzen Rationen mit verschiedenen Stärkearten (gekochte Maisstärke = MSc, rohe Maisstärke = MSr, rohe Kartoffelstärke = PSr, Stärkeaufnahme 4,7–8,9 g/kg Körpermasse). Als kohlenhydratfreie Kontrollrationen dienten 2 fettreiche (FATc und FATr) und eine eiweißreiche Ration (PROT). Neben der Verdaulichkeit der Stärke (insgesamt und praecaecal) wurde der Einfluß der Stärke auf die Protein- und Fettverdauung sowie auf das intestinale und faecale Milieu (pH, Trockensubstanz, Osmolarität, organische Säuren, Pufferkapazität, Ammoniak, in-vitro-Gasbildungsvermögen) geprütt. In einem weiteren Versuchsansatz wurde der Einfluß der Darmflora durch hochdosierte orale Antibiotika (500 mg Ampicillin, 75 mg Clindamycin, 12,5 mg Enrofloxacin/Tier/d) weitgehend ausgeschaltet. Die Stärkeverdaulichkeit betrug bei MSc beinahe 100%, bei MSr 78% und bei PSr nur 36%. Die praecaecale Stärkeverdaulichkeit (post mortem durch Marker ermittelt) war niedriger als die Gesamtverdaulichkeit, es ergab sich jedoch eine ähnliche Abstufung (MSc 72, MSr 46, PSr 0%). Bei den Rationen mit roher Stärke (MSr und PSr) ging die Proteinverdaulichkeit zurück, während die Fettverdaulichkeit zunahm. Die Aufnahme von Stärke führte zu einer Säuerung des Chymus. Dieser Effekt wurde durch orale Antibiose deutlich gemildert. Die Konzentration der organischen Säuren im Chymus bzw. Kot wurde sowohl durch Stärke als auch durch orale Antibiose beeinflußt. Das in-vitro-Gasbildungsvermögen des Kotes war nach Stärkefütterung signifikant gröfier.
Koblenhydratstoffwechsel der Katze 1. Aktivität der Amylase im Verdauungskanal
Erwachsene Katzen erhielten entweder eine von 3 verschiedenen stärkereichen Rationen (gekochte bzw. rohe Maisstärke, rohe Kartoffelstärke, 30–37% Stärke in der Trockensubstanz) oder eine kohlenhydratfreie Kontrollration. In Pancreas, Chymus und Faeces wurde die Aktivität der Amylase bestimmt. Außerdem erfolgte eine Charakterisierung der Amylase aus Pancreasgewebe und Kot (pH-Optimum, Bindung an Partikel, Aktivität im Bakteriensediment, Säurestabilität, Einfluß von in-vitro-Fermentation). In einem weiteren Versuchsdurchgang wurde der Effekt oraler Antibiose (500 mg Ampicillin, 75 mg Clindamycin, 12,5 mg Enrofloxacin/Tier/d) auf die Amylaseaktivität im Kot überprüft. Chymotrypsin wurde in Chymus, Kot und nach in-vitro-Fermentation bestimmt. Die Aktivität der Amylase im Pancreas und Chymus war relativ gering (Pancreas 75 U/g, Dun̈ndarmchymus 10–50 U/g Frischgewicht). Es trat nur ein geringer Induktionseffekt durch Stärke im Futter auf, nach sehr langfristiger Stärkefütterung verdoppelte sich die Aktivität im Dünndarm. Die Amylaseaktivität nahm nach caudal ab. Die große Ähnlichkeit der faecalen Amylase mit der Pancreasamylase bei der Charakterisierung, das Ausbleiben einer systematischen Veränderung der Aktivität im Kot bei oraler Antibiose sowie der Rückgang bei in-vitro-Fermentation sprechen dafür, daß der überwiegende Teil der Amylase im Verdauungskanal der Katze aus dem Pancreas stammt.
Zusammenfassung
Kohlenhydratstoffwechsel der Katze. 3. Verdauung von Zuckern
An 12 erwachsenen Katzen wurde die Gesamtverdaulichkeit von Glucose (5,1 g/kg Körpermasse), Galactose (5,6 g/kg Körpermasse), Lactose (1,3 und 4,5 g/kg Körpermasse) und Saccharose (7,2 g/kg Körpermasse) sowie die praecaecale Verdaulichkeit von Lactose und Saccharose (post‐mortem‐Versuche mit Chromoxid als Marker) ermittelt. Außerdem wurde der Einfluß dieser Zucker auf die Protein‐ und Fettverdaulichkeit sowie den Intestinalstoffwechsel (Wasser, pH‐Wert, organische Säuren) überprüft. Die Gesamtverdaulichkeit der Zucker betrug in allen Fällen nahezu 100%, die praecaecale Verdaulichkeit von Lactose in der höheren Dosierung 70,5 und von Saccharose 98,8%. Die scheinbare Verdaulichkeit des Proteins wurde durch Saccharose oder Lactose (beide Dosierungen) im Vergleich zur kohlenhydratfreien Kontrollgruppe um 4 bis 5% verringert. Glucose und Galactose übten keinen signifikanten Effekt auf den Kot‐pH‐Wert aus (Glucose 7,15, Galactose 6,96, kohlenhydratfrei 7,22), die anderen Zucker bewirkten jedoch eine mehr oder weniger starke Ansäuerung der Faeces (Saccharose 6,00, Lactose, höhere Dosis 5,36, kleinere Dosis 6,38). Der pH‐Wert im Magen und Dünndarm wurde durch Zuckerfütterung nicht verändert, im Dickdarm traten nach Lactose‐ bzw. Saccharoseaufnahme jedoch ähnliche Effekte auf wie im Kot. Außer bei Saccharose ging der Gehalt an kurzkettigen Fettsäuren (SCFA) im Kot nach Zuckeraufnahme zurück, während die Lactatkonzentration anstieg. Diese Veränderungen waren bei der hohen Lactosedosis am deutlichsten ausgeprägt (kohlenhydratfreie Ration: SCFA 307, Lactat 0,71 mmol/kg Kot; Lactose: SCFA 58, Lactat 14,27 mmol/kg). Während der Trockensubstanzgehalt im Kot nach Aufnahme von Monosacchariden anstieg, führten Disaccharide zu einer mehr oder weniger starken Zunahme des Wassergehaltes. Lactose und Saccharose bewirkten im Dünn‐ und Dickdarm ebenfalls einen Rückgang des Trockensub‐stanzgehaltes im Chymus.
The activities of three urea cycle enzymes, several nitrogen catabolic, gluconeogenic, and lipogenic enzymes were measured in the liver of adult cats fed: a commercial kibble; a 17.5 or 70% protein purified diet, or starved for 5 days. Except for an increase in tyrosine transaminase (EC 2.6.1.5) after feeding the high protein diet, there were no changes in the activities of the hepatic enzymes as influenced by dietary protein level. Likewise, starvation had a minimal effect on the activities of these enzymes as compared to that found in similar experiments in rats. These results indicate that the cat may have only minimal capabilities for enzyme adaptation as compared to that found in many herbivores and omnivores and may provide an explanation as to why cats have an unusually high protein requirement as compared to many other mammals.
Cats fed a diet containing linoleate as the only polyunsaturated fatty acid showed extremely low levels of arachidonate in the plasma lipids, as well as an increase in linoleate, eicosadienoate and an unknown fatty acid. Administration of [1-14C]linoleic acid and [2-14C]eicosa-8,11,14-trienoic acid to cats showed that in the liver there was no conversion of the [1-14C] 18:2 to arachidonate, whereas there was significant metabolism of [2-14C] 20:3 to arachidonate. It was found when methyl-gamma-linolenate was fed to cats that the level of 20:3 omega 6 and 20:4 omega 6 in the erythrocytes increased significantly. These results show that there is no significant delta 6 desaturase activity in the cat, whereas chain elongation and delta 5 desaturase enzymes are operative. The unknown fatty acid was isolated from the liver lipids and shown to be a 20-carbon fatty acid with 3 double bonds and which by gas liquid chromatography could be separated from 20:3 omega 9 and 20:3 omega 6. The presence of the delta 5-desaturase activity and the results of the ozonolysis studies indicated that this unknown fatty acid was eicosa-5,11,14-trienoic acid.
The reproductive performance and outcome of kittens was determined for female cats fed 0.05, 0.2 or 1% taurine. No adverse effects of high taurine diets were noted in the adults or offspring, and the reproductive performance was slightly better than that of females fed the normal (0.05% taurine) diet. Body weight at birth and brain weight at weaning were significantly greater in the very high taurine group than in the normal taurine group, although the greatest growth rate was achieved by the normal taurine group. The concentration of taurine in milk of lactating females was substantially higher in cats fed the higher taurine diets. Brain of adult cats was resistant to increases in brain taurine concentrations, as was brain of newborn cats. However, brain of juvenile cats responded to higher dietary taurine intake with increased taurine concentrations. These results indicate that the higher taurine content in cat foods recently introduced for prevention of feline dilated cardiomyopathy should have no adverse effects over a prolonged period on health and reproduction of cats.
Cats were fed 17.5% (LP) and 70% (HP) diets and hepatocytes were prepared from them. Rates of gluconeogenesis from pyruvate, alanine and threonine (10 mM) were unaffected by protein intake but 10 mM glutamine was converted faster by cells from HP fed animals. Rates of oxidation of alanine, threonine and glutamine and flux rates of tyrosine aminotransferase and tryptophan 2,3-dioxygenase were greater in cells from HP fed cats at all amino acid concentrations used. Proteolysis was indicated by urea production which was higher in cells from HP fed cats but was reduced significantly by leupeptin.
Cats given DL-methionine (1 g/kg of body weight/day) developed severe hemolytic anemia with marked increase of methemoglobin (MetHb) concentration and Heinz-body formation at treatment-day 6 to 10. Cats fed 0.5 g of methionine/kg for 52 days had a moderate Heinz-body hemolytic anemia with methemoglobinemia at treatment days 17 to 31, but thereafter recovered from the anemia despite continuation of methionine feeding, indicating an adaptation of the cats. In vitro, significant (P less than 0.01) increases of MetHb concentration and Heinz-body formation were observed when RBC were incubated with plasma from cats fed (1 g of methionine/kg) or with 10 mM 3-methylthiopropionate, a product of methionine catabolism. However, these increases were not observed when RBC were incubated with 10 mM methionine. Seemingly, excessive methionine intake leads to production of an intermediate of the methionine catabolism that may affect RBC directly as an intensive oxidizing agent, resulting in an excessive oxidation of hemoglobin to MetHb and Heinz-body formation.
Body proteins in cats were prelabelled with [14C]valine, and protein degradation was studied in isolated hepatocytes. Amino acids appeared to have a direct inhibitory effect on protein degradation, but the effects were generally smaller than those previously shown in the rat. The amino acid control of protein degradation in the cat differs from that in the rat, as shown by the lack of effects of glutamine, asparagine, arginine or methionine in cat hepatocytes. This may be related to the unique features of protein metabolism of this species. NH4Cl, leupeptin and amino acids, which suppress lysosomal protein degradation by different mechanisms, caused less than 30% inhibition of protein degradation when used at the optimum concentrations reported for the rat. The ability of the lysosomal system to respond to nutritional deprivation is apparently lower in the cat than in the rat.
Body condition was assessed by owners and veterinarians for over 2000 cats presented to 31 private veterinary hospitals in the Northeastern United States. Each owner completed a questionnaire querying potential factors associated with his/her cat's body condition. Veterinarians reported twenty-five percent of cats were overweight (heavy or obese), while owners estimated 29% of their pets were overweight. Apartment dwelling, inactivity, middle age, being male, neutered, of mixed breeding, and certain dietary factors were associated with being overweight.
To determine the association between body condition and disease in cats.
Prospective study.
Information on 1,457 cats without major illnesses from 27 veterinary hospitals in the northeastern United States.
Cats that had body conditions determined from 1991 to 1992, using a set of 6 body condition silhouettes, had their health experiences and body conditions assessed for the subsequent 4.5 years. Cats were described by the following 6 body conditions: cachectic, lean, optimally lean, optimal weight, heavy, and obese. Data obtained from medical records and owner interviews were collected, using standard forms. Associations between body condition and specific diseases were analyzed. Findings in cats with body conditions other than optimal were compared with findings in cats with optimal body condition.
Compared with optimal weight cats, heavy cats were 2.9 times as likely to be taken to veterinarians because of lameness not associated with cat bite abscesses. Obese cats were also 3.9 times as likely to develop diabetes mellitus, 2.3 times as likely to develop nonallergic skin conditions, and 4.9 times as likely to develop lameness requiring veterinary care. Cats considered thin (cachectic and lean) were 1.7 times as likely to be presented to veterinary hospitals for diarrhea.
Results of this study substantiate reports of health risks associated with excess body weight in cats. Efforts to reduce weight in heavy and obese cats can lead to reduced risks of diabetes mellitus, lameness (presumably related to osteoarthritis and soft-tissue injuries), and skin problems unrelated to allergies. Cachectic and lean cats are more likely to have diarrhea that is not associated with a definitive diagnosis.
Kittens fed diets containing 2.0 and 3.0 times (x) the NRC (1986) essential amino acid (EAA) requirement (EAArq) and 210 to 560 g crude protein (CP)/kg diet had growth rates and plasma amino acid patterns that were not significantly different than kittens fed a control diet (CD) containing 1.5 x EAArq and 350 g CP/kg diet. Growth rates of kittens fed diets containing only EAA (with nontoxic levels of arginine and methionine) and 280 to 460 g CP/kg diet were equivalent to those of kittens fed CD. Kittens fed only EAA and 140 and 210 g CP/kg diet had growth rates that were significantly lower than kittens fed CD. Since the growth rate of kittens fed 1.5 x EAArq and 210 g CP/kg diet in a previous experiment was equivalent to kittens fed CD (Taylor et al., 1997), it is suggested that the requirement for CP is higher (up to 280 g CP/kg diet) when only EAA are fed. The higher crude protein requirement appears to be primarily a consequence of the high obligatory nitrogen loss as urea (especially from arginine) incurred in the conversion of nitrogen from EAA to dispensable amino acids in the liver and secondarily because of a slow rate of catabolism of the EAA. A 3-dimensional plot of weight gains vs. CP levels and EAA to total nitrogen (E:T) ratios of kittens shows a broad range of CP levels and E:T ratios that support optimal growth in the kitten. It is suggested that similar patterns would occur in the chick, rat and other species if adverse effects caused by excesses of specific amino acids are avoided.
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